Water power

Water, together with the Sun, are the main sources of life and we depend on them for many fields where they are applied. Since the beginnings of civilization, men used this element not only for nourishment, but also as a propeller for devices (Roman watermills, Muslim watermills, steam engines...) But it was with the discovery of electricity and its applications at the end of the 19th century when water played a key role in the industrial and technological development.

In 1880, the first water powered machine to transform water power into electricity was made in Northumberland (Great Britain). Later, in 1882, another water power station was built in Appelton (Wisconsin, USA).

In Spain, this technology took very little time to be used and in 1901, the two first water power stations were started: “El Porvenir” in the river Duero (Zamora) and the “Molino de San Carlos” in the river Ebro (Zaragoza).

But it was with the alternating current when water power really became important. Several companies were set up as a result of the assosiation of businessmen at that time: Sevillana de Electricidad in 1894, Hidroeléctrica Ibérica in 1901, Hidroeléctrica Española in 1907, Iberduero as a result of the merging of Hidroeléctrica Ibérica with Saltos del Duero in 1918. Later, other companies were created: Eléctricas Reunidas de Zaragoza (1911), Unión Eléctrica Madrileña (1912) and Hidroeléctrica del Cantábrico (1919).

The way a water power station works consists of transforming kinetic energy from controlled water torrents that go through a turbine which is connected to an alternating-current generator.

These are the different types of water power stations:

Reversible power stations: they base their functioning on the pumping stations.

Flowing water power stations: placed in the shallow part of a river, they take water up to the station to readdress it to the turbine.

Reservoir power stations: placed on the side of a reservoir or dam, they use water allocations to create water torrents placed at height so that water goes through a turbine placed down. They can be subdibided according to working pressure into:
- High pressure power stations: when water torrents are more than 200 metres up the turbine.
- Medium pressure power stations: water torrents placed between 20 and 200 metres up the turbines (normally Francis turbines)
- Low pressure power stations: when torrents are placed less than 20 metres up the turbines (normally very fast Francis turbines, propeller turbines or Kaplan turbines).

The diameter and speed of the turbines will depend on the power we want to obtain, being the most powerful those with the longest diameter and the lowest spinning speed.

In Spain, water power has been terribly affected over the last years due to droughts. The development of mini and micro power stations could contribute to the increase in the production of electricity in Spain using this system. That is why research in this field has to be fostered and supported so as to make these systems more competitive.

Source: Ecological Research Institute.

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